Mn-doped NiP2 nanosheets as an efficient electrocatalyst for enhanced hydrogen evolution reaction at all pH values

Abstract Developing stable and high-efficiency hydrogen generation electrocatalysts, particularly for the cathode hydrogen evolution reaction (HER), is an urgent challenge in energy conversion technologies. In this work, we have successfully synthesized Mn-doped NiP 2 nanosheets on carbon cloth (Mn-NiP 2 NSs/CC), which behaves as a higher efficient three dimensional HER electrocatalyst with better stability at all pH values than pure NiP 2 . Electrochemical tests demonstrate that the catalytic activity of NiP 2 is enhanced by Mn doping. In 0.5 M H 2 SO 4 , this Mn−NiP 2 NSs/CC catalyst drives 10 mA cm −2  at an overpotential of 69 mV, which is 20 mV smaller than pure NiP 2 . To achieve the same current density, it demands overpotentials of 97 and 107 mV in 1.0 M KOH and phosphate-buffered saline (PBS), respectively. Compared with pure NiP 2 , higher HER electrocatalytic performance for Mn−NiP 2 NSs/CC can be attributed to its lower thermo-neutral hydrogen adsorption free energy, which is supported by density functional theory calculations.